From the point of view of a beginning telecommunication system operator, such as a mobile phone operator, the focus is on increasing the coverage and capacity of the system. When a sufficient level has been reached in these areas, the operators begin to pay more attention to improving the quality of service. An important factor in quality improvement is to optimize the properties of the system for the needs of the users. In order to achieve this, the operator must get information both about the performance of its system and the behaviour of its users.
In FIG. 1, the operation of the mobile communication system 10 is shown as a simplified diagram. The system 10 in FIG. 1 comprises a base station 12, a mobile services switching centre (MSC) 13, a network management system (NMS) 14, a customer register 15 and a statistics unit 16. When the mobile station 11 is used, a connection is established between the mobile station 11 and the base station 12. Via the base station 12, the connection is transmitted to the MSC 13, which establishes a connection between the mobile station 11 and the intended destination. Information about the connection, the type of service offered and its duration is transmitted from the MSC to the customer register 15, in which the information is saved for invoicing.
By means of the network management system 14, the operation of both the MSC 13 and the whole mobile communication system 10 is monitored and also managed, when required. Information collected by the network management system 14 can be saved in the statistics unit 16 for statistical reference.
FIG. 2 is a flow chart of a prior art method 20, in which statistical material is collected for the needs of the system operator. The method 20 is based on examination of the statistical material about the use of a mobile communication system 10 received from the statistics unit 16. In a method like this it can be examined, for example, how large a proportion of the attempts to establish a connection succeeded in the area of each base station, or what the average duration of the connections in the system is.
In the first step 21 of the method 20, the parameter to be examined is defined. The information is collected in the second step 22. In the third step 23 of the method, the value of the parameter is added to the statistics, whereafter the process returns to step 22 for collecting more information, when needed. When the statistical data collected are regarded as sufficient, statistical analysis is carried out in step 24.
By carrying out statistical analyses, the method 20 described above can be used to calculate parameters essential for the mobile communication system from the statistical material obtained from the system, which parameters can then be used for optimizing the system, for example. However, the statistical quantities received from the use of the mobile communication system do not identify the users, but the statistics are compiled on the basis of measurable system parameters, and these parameters are not individualized by users.
FIG. 3 shows another prior art method, by which statistical material is collected for the use of the system operator. The method is built on the method 20 depicted above in FIG. 2, complemented with the method 30 based on a customer survey. The purpose of the customer survey is to find individual differences between users and to group the users according to their patterns of behaviour.
The parameter to be examined in the survey is defined in the first step 31, after which the actual customer survey 32 and compilation of statistics 33 is carried out. The statistical material received from the customer survey can be combined with the statistical material received from the mobile communication system by the first method 20, after which statistical analysis 24 is carried out on the combined material.
The prior art methods entail the problem that there is not a clear connection between the users and the parameters of the mobile communication system. Statistically it is possible to make comparisons between the statistical materials received with different methods and to try to connect the values of certain parameters measured from the system to certain classes of behaviour patterns of users defined on the basis of the customer survey. However, there is no certain connection between the classes of behaviour patterns and the parameters calculated from the operation of the system, because a certain user or class of behaviour pattern cannot be unambiguously combined with the quantities measured from the system.
Furthermore, the solution based on a prior art customer survey with questionnaires entails the problem of the reliability of questionnaire surveys in general. In practice, the person who carries out the survey does not have full certainty of to what extent the material collected with a customer survey really reflects the real situation and how much the personal opinions or assumptions of the users have influenced the results of the survey. For this reason, the best application of questionnaire surveys is in charting the opinions and expectations of users.